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Underfloor heating control panel

Adjusting to the falling temperatures in the colder months can be a challenge, with cold fingers and toes first thing in the morning being an uncomfortable reminder that winter is coming. Luckily your underfloor heating system is the perfect solution to take the chill off those first few steps!

If your underfloor heating system has recently been installed and you are looking to turn it on for the first time, or if it has been laid dormant for an extended period like over the summer, it is best to warm the system up slowly to avoid ‘shocking’ the system.

If your underfloor heating system has just been laid

Once your underfloor heating system is in place you may be eager to fire it up straight away, however if this is the first time you are using your UFH system it is important to check for a couple of things.

Is the screed fully dry?

One of the most important things to consider when your underfloor heating system has just been laid is whether the screed has fully dried. If the screed is still drying, heating the system up prematurely could cause cracking and damage, which will result in the flooring becoming uneven. It is important to let the screed fully dry naturally to remove the moisture and not to use the UFH system to speed this process up.

Different screeds will require different drying times. It’s always best to check with your installer if you are unsure what screed you are using for your UFH system.

What type of flooring are you using with your UFH system?

The type of flooring you have fitted can affect how you turn on your underfloor heating for the first time.

A timber floor, for example, can be sensitive to changes in temperature and should be gradually warmed to avoid warping.

It’s always best to check the flooring manufacturer’s guidance before turning on your underfloor heating.

If your system has been off for a while

You won’t need to use your UFH system all year round, even with the irregular British weather, so your system may lay dormant during the summer months.

When heating your system back up again after a long period, it is important to follow the same steps as when heating up your system for the first time. This allows your flooring to adjust to the raising temperature again.

Tiles on underfloor heating

What temperature should underfloor heating be run at?

As highlighted above, different materials for flooring react differently to the change in temperature from your UFH system.

Timber flooring

Warming the underfloor heating system up slowly, particularly for the first time, will help to minimise the risk of shocking the timber floor. We would suggest turning the heating mixing valve (or heat pump maximum flow temperature) to 40˚C, and then increasing by 5˚C per day up to the design temperature shown on Nu-Heat’s Manifold & Zone Information Sheet.

Stone and ceramic

Stone and ceramic tiles are more resistant to heat and won’t shock like timber but it’s advised that a decoupling membrane is used when fitting a tiled floor over UFH. The decoupling membrane will be resistant to high temperatures. It is still advisable to check with your tiling manufacturer on the temperature that the tiles can heat up to, just to be on the safe side.

Vinyl and linoleum flooring

As with timber, vinyl or linoleum flooring should be laid flat for a minimum of 24 hours prior to installation. The temperature of the room it is in should be between 18–26˚C, but the underfloor heating should not be used to achieve this temperature.

The underfloor heating should be tested and switched off 48-hours before installation of the flooring and remain off during installation and for 48 hours afterwards.

The adhesive used to fix the vinyl or linoleum flooring should be sufficient to sustain the working temperature of the underfloor heating, up to a maximum of 27˚C.


The underfloor heating should be switched off 48 hours prior to laying and for 48 hours afterwards, before being brought up to full working temperature gradually over 7 days.

Check that the adhesives used to fit the underlay are suitable for use at normal underfloor heating operating temperatures.

How long does underfloor heating take to warm up?

Wet UFH systems use water from your boiler, which has to circulate through the system to deliver warmth. Electrical wire and mat systems heat up a lot faster from the electrical current running through them.

This means that wet UFH systems take a little longer to heat up but they will reach the desired temperature. If your floor feels like it isn’t heating up at first, wait a while rather than increasing the temperature to try and compensate.

The type of flooring will also have an effect on the time it takes to warm up. Tiles, stone and vinyl flooring will heat up fairly quickly while carpet and timber will take a little longer.

Smart Thermostats

Smart thermostats can be useful for automating your UFH system to suit you. They work with temperature sensors in the floor to heat up and maintain the temperature you want throughout the day.

With smart thermostats you can also set the time that you want the UFH system to come on, which is useful for heating your room for when you wake up, or for when you come home from work, and you can even control your heating from your smartphone.

Have any questions about turning on underfloor heating for the first time? Contact us!

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More about Jon Terry

As the Technical Service Manager at Nu-Heat, I am proud to support our customers through the life of their systems and to help customers with solutions to help them heat their homes in a better way.

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